Antioxidant



Patented July 2, 1940 AN TIOXIDAN T Waldo L. Semon, Silver Lake Village,Ohio, as-

signor to The B. F. Goodrich Company, New York, N. Y., a corporation ofNew York No Drawing. Original application November 2,

1934, Serial No. 751,263. Divided and this application June 19, 1937,Serial No. 149,204

12 Claims.

This invention relates to the art of rubber manufacture and has as itsobject to provide a new and extremely efiective class of antioxidants,which, when added to rubber, will greatly retard its deterioration.

This new class of antioxidants may be designated as N-mono-aryldecahydronaphthylamines. The word aryl is here employed to designatearomatic hydrocarbon radicals having a single free valence on anaromatic nucleus, and the term mono-aryl is employed to designatecompounds containing only an aryl radical substituted on the nitrogen ofthe amine and which are therefore secondary amines.

A specific example of one of these new antioxidants is phenyldecahydronaphthylamine (either alpha or beta), which may be obtainedreadily by catalytic reduction of phenyl naphthylamine (alpha or beta,as the case may be) until the naphthalene nucleus is fully saturated. Atypical rubber composition may be prepared containing 100 parts byWeight of rubber, 45 parts of carbon black, 2 parts of zinc oxide, 2parts of stearic acid, 2 parts of pine tar, 3.25 parts of sulfur, 0.5part of polybutylidene-aniline and 1.6 parts (1% of the composition) ofthe antioxidant, and vulcanized for 60 minutes at 295 C. to give anoptimum cure. This composition resists deterioration and retains itsstrength and resiliency several times as long as the same compositionwithout the antioxidant. Similar results may be obtained with thebeta-naphthyl decahydronaphthylamine which can be obtained by thereduction of di-beta-naphthylamine, or indeed with any mono-aryldecahydronaphthylamine such as those derived from phenylalphanaphthylamine, o-tolyl beta-naphthylamine, mtolylbeta-naphthylamine, p-tolyl betanaphthylamine, p-cumylbeta-naphthylamine, alpha alpha dinaphthylamine, beta betadinaphthylamine, alpha beta dinaphthylamine, etc., by suitable methodsof reduction or otherwise.

It is a remarkable fact that although other mono-aryl alicyclic aminessuch as N-phenyl cyclohexylamine have little or no value asantioxidants, the decahydronaphthyl compounds of this invention areextremely active. They may be employed in any type of rubbercomposition, such as those used for automobile tires and tubes, hose,belting, sheet and thread rubber, rubberized fabrics, molded goods,seamless dipped goods, boots and shoes, etc., whether vulcanized in amold, in open steam, in hot air, or even vulcanized in the cold by theso-called acid process. The proportion of antioxidants may vary fromabout 0.1% to 5%, although either smaller or greater proportions may befound useful, and

milling or mastication, their addition to an aqueous dispersion such asrubber latex in a finely dispersed form, their solution in a liquid, andany equivalent methods such. as applying them to the surface ofvulcanized or unvulcanized rubber in the form of a powder, paste orsolution. The term rubber unless otherwise limited is likewise employedin a generic sense to include caoutchouc, balata, gutta-percha,reclaimed rubber, synthetic rubber, artificial rubber isomers, and likeproducts, whether vulcanized or unvulcan-' ized and whether or notadmixed with fillers, pigments, vulcanizing and accelerating agents.

This is a division of my copending application Serial No. 751,263 filedNov. 2, 1934.

I claim:

1. The method of preserving rubber which comprises treating rubber witha secondary aryl decahydronaphthylamine.

2. The method of preserving rubber which comprises treating rubber witha secondary phenyl decahydronaphthylamine.

3. The method of preserving rubber which comprises treating'rubber withphenyl alphadecahydronaphthylamine.

4. The method of preserving rubber which comprises treating rubber withphenyl betadecahydronaphthylamine.

5. The method of preserving rubber which comprises treating rubber withbeta-naphthyl decahydronaphthylaminc.

6. The method which comprises vulcanizing rubber comprising a secondaryaryl decahydronaphthylamine.

'7. A rubber composition containing a secondary aryldecahydronaphthylamine.

8. A rubber composition containing a secondary phenyldecahydronaphthylamine.

9. A rubber composition containing phenyl alpha-decahydronaphthylamine.

10. A rubber composition containing phenyl beta-decahydronaphthylamine.

11. A rubber composition containing betanaphthyl decahydronaphthylamine.

12. A vulcanized rubber composition containing a secondard aryldecahydronaphthylamine.

WALDO L. SEMON.

